September 13, 2012

First African Monkey Species Identified In Seven Years

A new species of monkey discovered in the Democratic Republic of Congo is the second to be identified in 28 years (sun-tailed monkey, c. 1984) and the first since the Kipunji was discovered in Tanzania in 2003. The discovery is published in the open-access journal Public Library of Science (PLoS One).

The new species, Cercopithecus Lomamiensis, known locally as “lesula,” has been a well-known occupant of the remote forests of the Congo for hunters, but remained unknown to the outside world. The species is separated from its nearest cousins by two rivers: the Congo and the Lomami.

The first specimen was recorded when scientists found a young captive animal in 2007 at a school director´s compound in the town of Opala in the Congo.

“We never expected to find a new species there,” said lead scientist John Hart, of Yale University's Peabody Museum of Natural History . “But the Lomami basin is a very large block that has had very little exploration by biologists.”

“Our Congolese field teams were on a routine stop in Opala. It is the closest settlement of any kind to the area of forest we were working in,” he added.

The monkey bore a resemblance of the owl face monkey, but its coloration was unlike that of any other known species. It had strikingly large, almost human like, eyes, a pink face and golden mane. Its sunken eyes are set deep in a dark face, and a white stripe runs down from its brow to its mouth.

“I got in touch with geneticists and anthropologists to get their advice. I knew it was important to have a collaborative team of experts,” said Mr. Hart, who made the discovery along with his wife, Terese.

The Harts then spent three years working with field teams locating additional lesula in the wild, and over time were able to determine the monkey´s genetic and anatomical distinctions, behavior and ecology.

The monkey lives mostly in small groups of one to five; during eight separate encounters only once have researchers encountered a specimen all alone. In one encounter, which has been described as an “exceptional sighting,” researchers observed a crowned eagle attacking and killing a female lesula.

The field teams collected specimens from hunters and monkeys killed by leopards, and also the one specimen killed by the eagle (the worker had to wait for the eagle to leave its perch, explained Hart). The specimens were shipped to research centers in the US and data was shared with labs across the country.

The difference in appearance between the lesula and the owl face monkey was striking, noted Christopher Gilbert, an anthropologist at Hunter College in Manhattan.

“After comparing the skins, we immediately concluded that this was probably something different that we had seen before,” Gilbert, an expert in primate and monkey evolution, told CNN´s David McKenzie.

The skulls of the lesula were compared to those of the owl face and were digitally drawn in 3D. “We looked at the difference in shape and a number of landmarks in the skulls,” Gilbert said. While the two species had similar sized skulls, the Lesula had significantly larger orbits and several other small, but statistically significant, differences in the hard anatomy of the skull.

Scientists from New York University and Florida Atlantic University backed up those claims with genetic analysis, and traced the two lineages to a common ancestor. Researchers believe the two monkey species evolved separately after a series of rivers separated their habitats.

“The clincher was that lab and field teams were able to document significant difference in conjunction with the genetics. The monkeys were different and have been different for a couple of million years. It demonstrates that there are places in the world that we do not know much about,” said Gilbert.

The lesula´s range covers about 6,500 square miles in central Congo, in what was one of the region´s last biologically unexplored forest blocks. Although the range is remote and only lightly settled by humans, the species is threatened by local bush meat hunting.

“The challenge for conservation now in Congo is to intervene before losses become definitive,” said the Harts, who also run the Lukuru Wildlife Research Project. “Species with small ranges like the lesula can move from vulnerable to seriously endangered over the course of just a few years.”

Mr. Hart said he hopes the announcement of the new discovery will bring a renewed sense of vigor in preserving a region under constant threat from logging, hunting and weak government structure.

The Harts´ Lukuru Foundation is working with Congolese authorities to establish a national park in the Lomami basin before its unique biodiversity is lost for good.

“The challenge now is to make the Lesula an iconic species that carries the message for conservation of all of DR Congo's endangered fauna,” said Mr. Hart. He hopes that with proper protection, the lesula, and the rest of Lomami´s incredible animal biodiversity, will not perish.

“The discovery of the lesula has extended our knowledge of the evolution and ecology of African monkeys, and in particular has confirmed the importance of a previously little-known region for primate diversity,” he told Ella Davies of BBC News, Nature.

“This discovery may be only the first from this remarkable but poorly known forest, located in the central DRC [DR Congo],” said anthropologist Andrew Burrell from New York University who was also involved in the study. “Recent surveys have shown that the forest also harbors okapi, bonobos and elephants, as well as 10 other primate species or subspecies.”